Rebuilding old 1980 XS11 special

[gnosis]

Hi folks
I could really use some help. I'm real happy to have found this group

I'm new here and very new to the XS11. Funny, I used to own an XS11 with full Vetter fairing and bag package which never ran so I never got to enjoy it. I sold it for very little money because I didn't have the time, space or money to work on it then.

With my new '80 XS11 Special project which hasn't run for 9 years, I have cleaned the carbs, replaced the boots, petcock seals, gas tubing and air box. Put gas in the tank, set petcocks to prime and gas leaked out the airbox. No leaks when petcocks were in "on" or "res" positions. Engine starts at idle but does not keep running for more than a few seconds and stops immediately if you open the throttle.

Any ideas what I may be doing wrong would be appreciated.
Thanks,
Paul

[tcoop]

One, you have a stuck float (that's why it leaks on prime)
two, carbs probably needs to be synced (hard to do if it only runs for a few seconds)

you need to check the valve shim clearance make sure they are in spec.
bench sync you carbs (butterflies set to be the same)
If there is any rust in your tank, put in-line fuel filters to catch anything from the tank

[gnosis]

Thanks tcoup
After having read rebuilding carbs 101 I see I was not thorough enough in the job I did.Back to the drawing board.

[TopCatGr58]

Thanks tcoup
After having read rebuilding carbs 101 I see I was not thorough enough in the job I did.Back to the drawing board.

Hey Paul,

No, not the drawing board, just the 2nd cleaning of what most folks end up doing is a Triple Clean! However, if you're fastidious enough, you may only need the 2nd one. The Pilot circuits are small and finicky, and both them and the pilot jets are probably clogged, that's why no throttle response, no fuel is getting thru! IF yours are the later production line of 80's carbs, then you should have the plastic floats, and the viton/rubber tipped float valves. They can harden and form a groove in them after many years, you may need to replace them to prevent them from leaking/flooding.

Hopefully you're just new to the XS11 and not to biking in general?? Once you get it running, you'll see why we love them so much!

T.C.

[gnosis]

Thanks topcat
I'll be a lot more fastidious this time.
I'm certainly not new to biking. I had an 83 Kawi KZ1100 years ago which was probably the best bike of many I've owned (except for maybe my 87 Venture). Can't wait to get the XS running to feel that inline 4 feeling again.
My carbs have the metal floats, so they must have been early 80's production.

[ViperRon]

Clean your Tank any rust causes petcock and carb issues.

[fredintoon]

- - - With my new '80 XS11 Special project which hasn't run for 9 years, I have cleaned the carbs, replaced the boots, petcock seals, gas tubing and air box. Put gas in the tank, set petcocks to prime and gas leaked out the airbox. No leaks when petcocks were in "on" or "res" positions. Engine starts at idle but does not keep running for more than a few seconds and stops immediately if you open the throttle.
Any ideas what I may be doing wrong would be appreciated.
Thanks,
Paul

Hi Paul and welcome,
the usual blocked idle jets symptom is "will not run below 3,000 rpm" rather than "only runs briefly at idle."
Besides the true "clean the carbs yet again" advice, have you checked that the octopus (central vacuum operated gas opener) valve is working?
Your "on" and "res" positions are still "off" positions if the octo is dead.

[TopCatGr58]

Thanks topcat
I'll be a lot more fastidious this time.
My carbs have the metal floats, so they must have been early 80's production.

Hey Paul,

Okay, there's a tech tip on how to identify which model/style of carbs you have, take a look. In the early part of the 80 model production runs, they used some leftover parts and came up with some bastardized carbs.

These had the smaller MAIN jets like the later style, but also had the emulsion tubes that worked with the shared tunnel that is between the pilot and main jet towers, and so they put in Rubber caps that closed off the Pilot jet towers so that they would feed thru the Main Jet/shared tunnel. Later when they ran out of these bodies, they then opened/uncapped the pilot jet towers, and both the main and pilot jets fed directly from the float bowl.

So....if yours is the bastardized version and you do NOT have the pilot jet towers capped, that can cause some severe rich condition and trouble tuning and such!

Once your float valves are working/sealing properly, you can use PRIME to run on to get it running, and then you can see if it will run in the petcock ON position. IF not, and you still have the Octy, then further diagnostics will be required to determine what's wrong with the Octy...cracked vac. line, or damaged/stuck vac. valve, etc.! Some keep the Octy, and repair, others just chunk it in the trash bin and bypass all of that extra fuel line, and then just remember to turn OFF the petcocks when parked to take the stress off of the float valves, and to prevent a possible fuel in oil event IF the float valves were to fail/leak!

Glad to hear your a veteran biker!

T.C.

[fredintoon]

Hey Paul,


These had the smaller MAIN jets like the later style, but also had the emulsion tubes that worked with the shared tunnel that is between the pilot and main jet towers, and so they put in Rubber caps that closed off the Pilot jet towers so that they would feed thru the Main Jet/shared tunnel. Later when they ran out of these bodies, they then opened/uncapped the pilot jet towers, and both the main and pilot jets fed directly from the float bowl.

So....if yours is the bastardized version and you do NOT have the pilot jet towers capped, that can cause some severe rich condition and trouble tuning and such!
Once your float valves are working/sealing properly, you can use PRIME to run on to get it running, and then you can see if it will run in the petcock ON position. IF not, and you still have the Octy, then further diagnostics will be required to determine what's wrong with the Octy...cracked vac. line, or damaged/stuck vac. valve, etc.! Some keep the Octy, and repair, others just chunk it in the trash bin and bypass all of that extra fuel line, and then just remember to turn OFF the petcocks when parked to take the stress off of the float valves, and to prevent a possible fuel in oil event IF the float valves were to fail/leak!
T.C.

Hi TC,
you sure about the 115 main jet size on the hybrid carb? If the pilot jet is fed through the slanty passage from the main jet won't it need the 137 main to work right? Or is the hybrid body different?
The carb kits ALL have those rubber plugs if you need them or not.
Coincidentally they fit inside the slow running needle jet access holes so they can be used to keep the needle heads dirt free after you've pried out and discarded the EPA's anti-adjustment plugs.
And yeah, one of my POs made the octo disposal decision for me so my Special tank had 2 gas lines instead of 8.
So's the current Standard tank. I also switched those gas taps to manual.
Just gotta remember to switch 'em off, is all.
Remembering to switch 'em on again is easy too after the bike starts to stutter 100 yards down the road.

[crazy steve]

Hi TC,
you sure about the 115 main jet size on the hybrid carb? If the pilot jet is fed through the slanty passage from the main jet won't it need the 137 main to work right? Or is the hybrid body different?

Fred, we've had this discussion and multiple owners with the 'hybrid' carb have stated that jetting is the same as the late carbs without the plugs. So there must be internal differences that we can't see...

Here's the carb identifier....

http://www.xs11.com/forum/showthread.php?t=35964